The purpose of this paper is to find calibration coefficients for antennae operating at the Lightning Research Station in Rzeszow. Two types of antennae used for acquisition of lightning electric field were examined. The first sensor was the ELF electric field mill registering slow electric field variations originated in the thunderstorm cloud. The second antenna was designed to recording relatively fast ELF-MF components of lightning as return stroke, continuing current and preliminary breakdown. In order to create uniform distribution of electric field during the calibration a dedicated setup was made in the high voltage laboratory. Different generators were used to create adequate field waveforms. Due to significant difference in amplification and bandwidth for each sensor. Devices were calibrated together with 10 meter cables dedicated for wiring signal from antenna to the A/D converter. Estimated calibration coefficients were 47.5 mV/kV and -334 mV/kV for the slow and fast electric field sensor, respectively. Small variation of those coefficients was observed when the signal transmission line was terminated by the characteristic impedance. Cable length does not affect the measured signals in this configuration.
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